The Suhua Highway, located in the northeastern part of Taiwan, is said to be one of the most dangerous highways worldwide. Due to the weak geology in this tropical area, heavy rain and typhoons during the rainy season cause a lot of landslides and interruptions, and the curved road located right between the precipitous mountain and the seaside provokes a lot of accidents. In order to increase security and boost tourism in this area, especially from China, the Ministry of Transportation and Communications (MOTC) is building 38,4km of tunnels and bridges to replace the three most dangerous sectors of the highway. The Project started 2011 and is expected to be completed in 2018.

MOTC has compared geological data from 275 drillings during the past 30 years and 27 recent drillings to make sure the soil and water conditions are adequate to support the construction. The building firm Kung Sing Engineering Corp., which is one of the biggest construction companies in Taiwan (based in Taipei) was assigned to plan the Suhua Highway Improvement Project. With its experience and expert knowledge of more than 50 years it plays a significant role in the important field of public works in Taiwan and the mainland.

Putzmeister Underground was commissioned by Kung Sing Engineering Corp. to provide 12 units of SPM 500 WETKRET concrete spraying systems for structural support in the roadway heading of the Kuan-yin (B2 section) and Ku-feng tunnel (B3 section). The equipment was sold to Kung Sing Engineering Corp. through Putzmeister’s Taipei-based distributor in Taiwan, Antung Group, which placed a repair shop on the jobsite, providing full service for the machines in use, including technical support, maintenance and spare parts. Antung´s Sales Engineer Jon Lai is always on-site and in charge of the operators’ training for the correct use of the machines.

The two tunnels have an overall length of approximately 13km, with the construction works being 7,94km and 4,66km each, with the corresponding costs for the 2 tunnels being NT $ 7,2 and NT$9.208 billion. The tunnels are being built by the New Austrian Tunnelling Method (NATM), with excavation by drill and blast. The top-heading-and-bench method is being used, whereby a smaller tunnel (top heading) is excavated first. Once it has advanced some distance into the rock, workers begin excavating immediately below the floor of the top heading creating a bench. One advantage of this method is that engineers can use the heading tunnel to gauge the stability of the rock before moving forward with the project.

“We are proud that our equipment meets the requirements of Kung Sing Engineering Group for concrete spraying in tunnel construction” said Max Eckstein, International Sales Manager of the Putzmeister Underground Division. The SPM 500 WETKRET series has been used in a large number of tunnelling projects all over the world. With a vertical spraying reach of 17m and a concrete flow of 30 m3/h, the machine is suitable for both medium and large section tunnels, galleries and slopes.